Rat Virus: Biological Threats, Symptoms & Prevention

A “rat virus” refers to a biological virus carried by rats that can be transmitted to humans, causing illness. While the risk for the average individual remains low, understanding these potential threats is important, especially for those in areas with rodent infestations or who own pet rats. This knowledge helps in taking informed precautions.

Common Viruses Transmitted by Rats

Hantaviruses are a family of viruses found globally, known to cause serious illness in humans. In North and South America, specific hantaviruses can lead to Hantavirus Pulmonary Syndrome (HPS), with the deer mouse, white-footed mouse, cotton rat, and rice rat being common carriers in the United States. Certain Old World hantaviruses, such as Seoul virus, primarily cause Hemorrhagic Fever with Renal Syndrome (HFRS) and are carried by rodents like the brown or Norway rat (Rattus norvegicus) and black rat (Rattus rattus) worldwide.

Lymphocytic Choriomeningitis Virus (LCMV) is another virus carried by rodents that can infect humans. The common house mouse (Mus musculus) is the primary natural host for LCMV, shedding the virus in their saliva, urine, and feces. Pet rodents can also become infected with LCMV, potentially transmitting it to humans.

How Rat Viruses Spread to Humans

Viruses carried by rats can spread to humans through several pathways. The most common route involves inhaling aerosolized viral particles from dried rodent urine, droppings, or nesting materials. When these contaminated materials are disturbed, such as by sweeping or cleaning, the virus can become airborne and be breathed in.

Direct contact with infected rodents or their excretions also facilitates transmission. This occurs when contaminated urine, droppings, or saliva directly touch broken skin, or come into contact with the eyes, nose, or mouth. Consuming food or water contaminated with rodent waste presents another potential route for infection. Although less common, a bite from an infected rodent can also transmit some of these viruses to humans.

Symptoms of Rat-Borne Viral Infections

Many rat-borne viral infections initially present with general, flu-like symptoms, making early diagnosis challenging. Common early signs include fever, headache, muscle aches, and fatigue. Patients may also experience nausea, vomiting, stomach pain, or diarrhea.

As Hantavirus Pulmonary Syndrome (HPS) progresses, more severe respiratory issues develop. This can lead to coughing, shortness of breath, and a feeling of chest tightness as fluid accumulates in the lungs. Lymphocytic Choriomeningitis Virus (LCMV) infection can also cause a biphasic illness, with an initial flu-like phase followed by a second phase that may include neurological symptoms such as meningitis or encephalitis, which can cause confusion or motor abnormalities.

Prevention and Safety Measures

Preventing exposure to rat-borne viruses involves environmental control and careful hygiene. Inside the home, seal potential entry points to deny rodents access, use traps to manage existing populations, and maintain high levels of sanitation to reduce available food and water sources. Removing clutter also eliminates potential nesting sites.

When cleaning areas contaminated by rodent waste, specific safety procedures are necessary to avoid aerosolizing viral particles. Do not sweep or vacuum dry droppings, urine, or nesting materials, as this can release the virus into the air. Instead, wear rubber, latex, or vinyl gloves, then spray the contaminated materials with a disinfectant solution, allowing it to soak. After soaking, carefully wipe up the materials with paper towels and dispose of them in a sealed plastic bag within a covered garbage can.

For individuals who own pet rodents, responsible care helps mitigate risks. Always wash hands thoroughly with soap and water after handling pet rats, their cages, or bedding. Regularly clean cages in a well-ventilated area, and avoid kissing or holding pet rodents close to the face to minimize direct contact with saliva.

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